The effect of fin types of the heatsinks on radiated emission on the printed circuit board at S‐C band

Abstract

AbstractHeatsinks are widely utilized to maintain the temperature of the electronic circuit components on the printed circuit board (PCB) within a certain range. Even they are thermally used for maximum cooling; they can also act as a source of electromagnetic (EM) radiation, causing EM interference (EMI) to their surrounding elements in certain cases. In this article, the heatsinks with various fin types such as plate‐fin, parabole‐plate fin, square‐pin fin, and circular‐pin fin are designed and fabricated to investigate EMI and thermal performances. The simulated and measured results of the reflection coefficient and normalized radiation pattern are obtained and compared in the S‐C band (2‐8 GHz). The dimension of the heatsink base regarding the patch antenna determines the first resonance frequency (4.75 GHz) while its height regarding the monopole antenna determines the second resonance frequency (6.75 GHz). It is aimed to investigate the effect of fin types of them and their orientation on radiated emission (RE) on the PCB. If the operating frequencies of the circuit elements near the heatsink are in the 2 to 3.4 GHz, 4.7 to 5.6 GHz, 5.6 to 6.15 GHz, and 6.85 to 8 GHz, it is preferable to use pin‐fin type instead of plate fins to reduce the RE from the heatsinks. However, in the 6.15 to 6.85 GHz, plate fins types should be preferred. All heatsinks regardless of fin types in the 2 to 2.2 GHz, 3.6 to 5.6 GHz, and 6.6 to 7.2 GHz should be located as horizontal. However, for 2.2 to 3.6 GHz, 5.6 to 6.6 GHz, and 7.6 to 8 GHz frequency bands, they should be located as vertical. Consequently, while pin‐fin type heatsink is preferred in 50% of the entire frequency band, it is better to use plate‐fin type heatsink in 35% of the band. Regardless of the type of heatsink used, it is significant to place the heatsink horizontally and vertically in 35% and 34% of the frequency band, respectively.